This invention relates generally to a manually operated dispenser having a reciprocable plunger head containing a discharge orifice through which product is dispensed upon head reciprocation. More particularly, the invention relates to a protector cap telescoped over the plunger head, normally covering the discharge orifice during non-use, and automatically uncovering the orifice prior to manual reciprocation of the head.
Manually actuated dispensers, such as pump dispensers and aerosols, are known for dispensing a variety of products upon finger actuation of a plunger head or spray button for effecting discharge of product through the spray orifice. The sprayed products may include hair sprays and other resinous containing materials which, upon drying, on exposure to the atmosphere, tend to clog the spray discharge orifice. Clogging interferes with the free flow of discharge by causing sputtering and uneven spray patterns.
Protector caps and covers have been devised to prevent the drying out of the discharged material in the discharge spout or orifice and to prevent its contamination. The known caps and covers employed for this purpose are, however, rather cumbersome, difficult to operate, costly to fabricate and somewhat ineffective. Moreover, they are so structured as to render them unwieldy and unattractive.
U.S. Pat. No. 3,254,677 discloses a resilient closure device mounted on the spray button of an aerosol dispenser to render the dispenser self sealing. The closure device is substantially U-shaped in cross-section having a pair of spaced arms. One of the arms seals off the discharge orifice from the atmophere in the normal position of the closure relative to the spray button. Such one arm has an aperture which is brought into registry with the discharge orifice upon manual application of a downward force on the closure.
The spray button has outwardly diverging grooves at the front face and at the back face thereof. In mounting, the arms of the closure are spread apart so that the ends of the arms fit into such grooves and are locked into place. Upon downwardly pressing the closure, the diverging surfaces on the spray button spread the arms apart and further distend the closure. At the same time the aperture in the front arm of the closure is brought into registry with the discharge orifice. When the closure bottoms out on the spray button, further downward movement of the closure serves to move the spray button downwardly while spraying through the uncovered orifice. Upon release of finger pressure applied to the closure, the closure springs upwardly relative to the spray button due to the resiliency from which the closure is made.
The drawbacks of such a closure or protective cap for a spray button are that the spray button must be specially designed as having front and back diverging grooves which renders the assembly more costly and difficult to produce and more cumbersome to operate. Moreover, the inherent resiliency of the spring legs of the closure must be relied upon to return the closure to its upper position of non-use each time finger force is removed therefrom. Since the closure is of a plastic material, it is known that this inherent resiliency or memory fails at some juncture after repeated use, such that the closure will not positively return to its upper position of non-use as intended. Also, each of the outwardly diverging grooves must be of a sufficiently steep angle to assure spring contraction of the closure arms to a less distended position during the upward return movement of the closure. However, because of space limitations of aerosol spray buttons which are typically quite small, steep angular grooves are not made possible.